getting error while running below query in sql

The multi-part identifier "a.DROI" could not be bound.
I am trying to update the Final_OD_Status table using RBL_Overdue_Daily

update Final_OD_Status
set
a.DROI = b.debit_rate_of_interest,
a.SL = b.sanctioned_limit,
a.PO = b.principal_outstanding,
a.emiam = b.emiamt,
a.PRIDUE = b.principle_due,
a.INTDUE = b.interest_due,
a.ODUES = b.other_dues,
a.PINDue = b.penal_due,
a.TOTDue = b.total_due,
a.DPD1 = b.dpd
from Final_OD_Status as a , RBL_Overdue_Daily as b
where a.account_no = b.account_no
and Loan_status = 'Not_paid'